The present invention relates generally to a mixing apparatus for mixing particulate solids into solution, and in particular for mixing bulk solutions of sodium bicarbonate for kidney dialysis. More particularly, the present invention relates to an apparatus for mixing purified sodium bicarbonate solutions for kidney dialysis in quantities to sufficient to supply dialysate for multiple kidney dialysis patients.
Heretofore, dialysis technicians were required to mix separate quantities of sodium bicarbonate solution for each dialysis patient. Dialysis technicians usually mixed premeasured sodium bicarbonate concentrate with medical purified water. This procedure has been found to be both labor and time intensive as well as uneconomical. Efforts have been made to provide devices capable of mixing bulk sodium bicarbonate dialysis solutions to serve the needs of multiple patients. Exemplary of these devices is the RS-2500 Mixing System for Sodium Bicarbonate Hemodialysis Concentrate sold by Renal Systems, a division of Minntech Corporation of Minneapolis, Minn. Renal System's RS-2500 consists of a fifty gallon mixing drum, a free standing mixing and dispensing pump consisting of a pump attached to jet mixing tubing and dispensing tubing, and a separate pump disinfection container having a dispensing hose and nozzle assembly attached thereto. In operation the dialysis technician fills the mixing drum with purified water, adds pre-measured dry sodium bicarbonate dialysis concentrate to the mixing drum; inserts the mixing and dispensing pump into the mixing drum and operates the pump until the concentrate is fully solubilized into solution. Dispensing is accomplished by operating the mixing and dispensing pump to draw the sodium bicarbonate solution out of the mixing drum for dispensing into storage tanks or individual patient containers. While Renal System's RS-2500 provides a means for mixing bulk sodium bicarbonate solutions from concentrate, it is an open system which exposes the solution to the ambient atmosphere during mixing, thereby increasing the risks of contamination. Moreover, the apparatus remains awkward and cumbersome to use.
In contradistinction to conventional bulk sodium bicarbonate dialysis solution mixing devices, the present invention is a closed circuit and consists of a bulk mixing and storage container, a recirculating pump connected thereto by inflow and outflow tubing having a series of valves for controlling flow direction and dispensing. Dispensing is controlled by a dispensing valve located at a bottom outlet port of the container. At no time during the mixing is the solution exposed to the ambient atmosphere, thereby limiting and minimizing contamination risks.
It has been found, therefore, that a need has existed for a sodium bicarbonate dialysis solution mixing apparatus which operates in a closed circuit and consists of a mixing and storage container operably coupled to a recirculation pump through a series of conducting inflow and outflow tubing wherein the direction of the flow is controlled by a series of valves.